Ro3280 is a selective inhibitor of PLK1 with IC50 value of 3 nM [1].
Polo-like kinase 1 (PLK1) is an enzyme and plays an important role in regulating cell cycles as an early trigger for G2/M phase transition. It has been shown that PLK1 is over-expressed in a variety of cancer cells and thus is regarded as a promising target for cancer drugs [2].
When tested with a panel of acute leukemia cell lines, Ro3280 showed inhibitory function on U937, HL 60, NB4, K562, MV4-11, and CCRF with IC50 value of 186 nM, 175 nM, 74 nM, 797 nM, 120 nM, and 162 nM, respectively. It was interesting to notice that ALL cells (35.49-110.76 nM) were more sensitive to Ro3280 compared with AML cells (IC50, 52.80-147.50 nM). Further, it was showed that Ro3280 treatment decreased cell viability, induced apoptosis and disrupted cell cycle [3]. In H82 (lung cancer), HT-29 (colon cancer), MDA-MB-468 (breast cancer), PC3 (prostate cancer), and A375 (cutaneum carcinoma), Ro3280 treatment inhibited PLK1 with the IC50 was 5 nM, 10 nM, 19 nM, 12 nM, and 70 nM, respectively [1].
In nude mice model with HT-29 cells subcutaneous xenograft, administration of Ro3280 caused significant anti-tumor activity with 78% reduction at the dose of 40 mg/kg, once a week and then completely regressed tumor when more drug and more frequent [1].
References:
[1]. Chen, S., et al., Identification of novel, potent and selective inhibitors of Polo-like kinase 1. Bioorg Med Chem Lett, 2012. 22(2): p. 1247-50.
[2]. Czaplinski, S., et al., Polo-like kinase 1 inhibition sensitizes neuroblastoma cells for vinca alkaloid-induced apoptosis. Oncotarget, 2015.
[3]. Wang, N.N., et al., Molecular targeting of the oncoprotein PLK1 in pediatric acute myeloid leukemia: RO3280, a novel PLK1 inhibitor, induces apoptosis in leukemia cells. Int J Mol Sci, 2015. 16(1): p. 1266-92.